Post-metal pioneers Isis, who broke up in 2010, will be sorely missed, a fact they reinforce with Temporal, a posthumous double-disc (plus DVD) full of pristine demos and other rarities. Aficionados will love picking out the differences between these early takes and the final album mixes: “Ghost Key” is instrumental here and the chirpy keyboards are missing, while “Carry” adds high-hat taps and more pronounced swells of guitar. But the album highlight is the completely new “Grey Divide,” a 16-minute thrill ride of tribal clamor and chiming atmospherics that illustrates what separated Isis from most post-metal bands—the need to push boundaries and the ability to mesmerize while doing so.–Revolver